A frilled shark (Chlamydoselachus anguineus) swims
above the sea floor. This species has been, on rare
occasion, caught or taken in bottom trawls. To the knowledge
of everyone on board the ship, however, this was the first time anyone
has ever seen it in its natural habitat. Identification was based on an approximately 30-s viewing and
videotaping of the specimen, noting diagnostic characters such as body
shape; snout length; mouth length and position; vertical fin length,
height, shape and placement; and by reviewing video clips and images of
previous submersible observations of hexanchiform sharks (bluntnose
sixgill shark, Hexanchus griseus (Bonnaterre, 1788) in the area (Barans
and Ulrich 1994; Weaver and Sedberry 2001).
The terminal mouth with narrow-cusped teeth, elongate eel-like body,
highly visible frilly gill slits, and the single and spineless low
dorsal fin posterior to the pelvic fins and above a long-based anal fin
confirmed the species identification.
The shark hovered in front of the submersible before turning sharply
toward and above the vehicle, revealing its terminal mouth and teeth. Video courtesy of Estuary to the Abyss 2004 Exploration, George Sedberry, NOAA-OE.